There has long been a debate over whether and to what extent stress may contribute to the development of cancer. Even though the National Cancer Institute reports research results that are mixed, a recent meta-analysis suggests that chronic stress is indeed linked to at least some cancers. In astrology, the celestial body Pluto is generally associated with death and transformation, and as such it is often seen as associated with stress. Furthermore, some astrologers even associate Pluto directly with cancer. In this study, squares in the birth chart between Pluto and other planets were examined with respect to associations with cancer, and two squares were found to be extremely significant when it comes to the likelihood of having cancer, namely Pluto square Uranus (p = 1.2 × 10-27) and Pluto square Chiron (p = 4.2 × 10-21). Furthermore, when these two conditions (Pluto square Uranus or Chiron) were combined, the likelihood of the observed results or something more extreme being due to chance was minimal at 1.2 × 10-44 those with this astrological signature were more than twice as likely to experience cancer (risk ratio = 2.07)). However, with results this extreme, there is always the concern that they might be statistical artefacts or due to some other variables that haven’t been considered. Additionally, even though some statistically significant results for Pluto square several of the faster moving planets were initially observed, these results were eventually shown to be statistical artefacts, and so this paper is also a cautionary tale for those engaged in research. One result involving cancer, Pluto, and a faster moving planet that was not shown to be an artefact, though, was the link between cancer and Pluto square the Moon (p = .0269). This result has added significance as some previous research (Minatel, 2015) has indicated a connection between the Moon and breast cancer.